Operating A Vessel Occlusion Catheter

ABSTRACT

Some systems and methods for operating a vessel occlusion catheter may include a control and inflation device to control the filling of the balloon in such a manner that the vessel wall will not be overstressed while the safe occlusion of the blood vessel is achieved.

CROSS-REFERENCES TO RELATED APPLICATION(S)

This application is a division of U.S. patent application Ser. No.13/688,725 filed on Nov. 29, 2012, which is a division of U.S. patentapplication Ser. No. 12/786,822 filed on May 25, 2010, which claimspriority to European Patent Application No. 10 450 019.4 filed on Feb.16, 2010. The entire contents of these previous applications areincorporated herein by reference.

TECHNICAL FIELD

This document relates to systems and methods for inflating and deflatinga balloon of a vessel occlusion catheter device arranged in a bodyvessel.

BACKGROUND

Balloon catheters have been used for a number of medical applications. Aballoon catheter comprises a balloon which can be brought from thedeflated state into the expanded state by the introduction of a fluid,and from the expanded state back into the deflated state by evacuation.The fluid may be comprised of a gas or a liquid.

Balloon catheters are, for instance, used for the balloon dilatation ofconstricted blood vessels in the context of a percutaneous transluminalangioplasty. In that case, a balloon attached to a vascular catheter isadvanced within a blood vessel as far a to a pathologically constrictedvascular site, and the balloon is deployed on the constricted site undera high pressure (6 to 20 bar). This causes the constrictions, which areprimarily due to arteriosclerotic vascular sclerosis, to be dilateduntil they will no longer, or less strongly, impair the blood flow.

Balloon catheters may, however, also be employed in the context of apressure-controlled intermittent occlusion of a body vessel and, inparticular, the coronary sinus. Methods for the pressure-controlledintermittent occlusion of the coronary sinus are, for instance,described in the documents EP 609914 A1, EP 230996 A2, EP 1406683 A2, EP1753483 A1, EP 1755702 A1 and WO 2008/064387 A1. In those methods, thecoronary sinus is cyclically occluded and released again by using aballoon, the occlusion of the coronary sinus, during the occlusionphases, inducing a pressure increase and hence a retroperfusion of bloodvia the respective vein into the nutritive capillaries of the ischemicregion so as to enable a redistribution of flow into those regions. Uponrelease of the occlusion, the retroperfused blood is flushed out whilemetabolic waste products are, at the same time, discharged. The pressurein the occluded coronary sinus is each measured during the occlusionphases, the release of the occlusion as well as the initiation of theocclusion occurring as a function of the measured pressure values.

As opposed to a balloon dilatation in the context of a percutaneoustransluminal angioplasty, the pressure-controlled intermittent occlusionof a blood vessel and, in particular, the coronary sinus does not aim toinflate the balloon with such a high pressure as to cause anirreversible deformation and, in particular, expansion of the respectivevascular region. The inflation of the balloon rather is to be controlledin a manner that the balloon exerts a pressure on the vessel wall, whichwill just do to occlude the blood vessel to a sufficiently safe extentand prevent blood from flowing past the balloon. If too high a pressureis fed to the balloon, this will cause too strong a radial expansion ofthe blood vessel, whereby the respective mechanical load on the vesselwall may lead to irreversible damage, which is to be prevented anyhow.On the other hand, too small a pressure supply to the balloon would savethe vessel wall, yet the balloon would not completely occlude thevessel.

SUMMARY

Some embodiments of a system or method for controlling the inflation ofa balloon catheter arranged in a blood vessel can provide a process bywhich it is feasible to control the filling of the balloon in such amanner that the vessel wall will not be overstressed while safelyoccluding of the blood vessel.

In particular embodiments, some systems and methods for operating avessel occlusion catheter may include a control and inflation device tocontrol the filling of the balloon in such a manner that the vessel wallwill not be irreversible deformed while the safe occlusion of the bloodvessel is achieved. For example, a coronary sinus occlusion catheter mayinclude a balloon device that is repeatedly inflated and deflated tointermittently occlude the coronary sinus. A control system for theocclusion catheter can include the control and inflation device havingcomponents to inflate and deflate the balloon device in a safe mannerthat reduces the likelihood of overstressing the vessel wall of thecoronary sinus.

The details of one or more embodiments of the invention are set forth inthe accompanying drawings and the description below. Other features,objects, and advantages of the invention will be apparent from thedescription and drawings, and from the claims.

DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective view of a portion of a system for treating hearttissue, in accordance with some embodiments.

FIG. 2 is a perspective view of another portion of the system of FIG. 1.

FIG. 3 is a block diagram of a control and inflation device of thesystem of FIG. 2.

Like reference symbols in the various drawings indicate like elements.

DETAILED DESCRIPTION

Referring to FIGS. 1-2, some embodiments of a system 100 for treatingheart tissue can include a coronary sinus occlusion catheter 120 and acontrol system 140 (FIG. 2). In particular embodiments, the controlsystem 140 can be configured to control the operation of the catheter120 for providing pressure-controlled intermittent coronary sinusocclusion (PICSO) and to receive heart sensor data for display. Thecoronary sinus occlusion catheter 120 includes a distal tip portion 121(leading to a distal end depicted in FIG. 1) and a proximal portion 131,which includes a proximal hub 132 that is coupled to the control system140 via a number of fluid or sensor lines 133, 134, and 135.Accordingly, the control system 140 may be employed to operate one ormore components at the distal tip portion 121 of the coronary sinusocclusion catheter 120 while also receiving one or more sensor signalsthat provide data indicative of heart characteristics (e.g., coronarysinus pressure, electrocardiogram (ECG) information, and the like).

Briefly, in use, the distal tip portion 121 of the coronary sinusocclusion catheter 120 can be arranged in a coronary sinus 20 of a heart10 and thereafter activated to intermittently occlude the blood flowexiting from the coronary sinus 20 and into the right atrium 11. Duringsuch an occlusion of the coronary sinus 20, the venous blood flow thatis normally exiting from the coronary sinus 20 may be redistributed intoa portion of heart muscle tissue 30 that has been damaged due to blooddeprivation. For example, the portion of heart muscle tissue 30 cansuffer from a lack of blood flow due to a blockage 35 in a coronaryartery 40. As a result, the arterial blood flow to the affected heartmuscle tissue 30 via a local artery 41 can be substantially reduced suchthat the heart muscle tissue 30 becomes ischemic or otherwise damaged.Further, because the arterial blood flow is reduced, the venous bloodflow exiting from the local vein 21 is likewise reduced. Other branchveins 22 located at different regions along the heart 10 may continue toreceive blood flow, thereby creating a supply of venous blood flowexiting through the coronary sinus 20. In some embodiments, the coronarysinus occlusion catheter 120 can be delivered into the coronary sinus 20and thereafter activated so as to intermittently occlude the coronarysinus 20 before, during, or after treating the blockage 35 on thearterial side. Such an occlusion can cause the venous blood flow to beredistributed to the local vein 21 and then into the portion of heartmuscle tissue 30 can suffer from a lack of blood flow due to a blockage35 in a coronary artery 40. As such, the ischemic or otherwise damagedheart muscle tissue 30 can be treated (e.g., reduction of border zoneinfarct size) with the redistributed venous blood flow in that the heartmuscle tissue 30 receives an improved redistribution of flow before,during, and after the blockage 35 is repaired or removed to restorenormal coronary arterial blood flow.

Furthermore, in use, the control system 140 (FIG. 2) is configured toprovide automated control of an occlusion component (e.g., an inflatableballoon 122 or the like) of the coronary sinus occlusion catheter 120.As described in more detail below, the control system 140 includes acomputer processor that executes computer-readable instructions storedon a computer memory device so as to activate or deactivate theocclusion in the coronary sinus 20 in accordance with particularpatterns. For instance, the control system 140 can be configured toactivate the occlusion component of the catheter 120 in the coronarysinus 20 as part of a predetermined pattern of occlusion periods andrelease periods that is independent of the coronary sinus pressure, oras part of a pressure-dependent pattern that is at least partiallydefined by the coronary sinus pressure readings during the procedure. Inaddition, the control system 120 is equipped with a display device 142having a graphical user interface that provides a cardiologist or otheruser with time-sensitive, relevant data indicative of the progress of acoronary sinus occlusion procedure and the condition of the heart 10. Assuch, the user can readily monitor the patient's condition and theeffects of intermittently occluding the coronary sinus 20 by viewing thegraphical user interface while contemporaneously handling the coronarysinus occlusion catheter 120 other heart treatment instruments (e.g.,angioplasty catheters, stent delivery instruments, or the like). Itshould be understood from the description herein that, in someembodiments, the control system 140 and the coronary sinus occlusioncatheter 120 can be used as part of a system for treating the heartmuscle tissue before, during, and after the blockage 35 is repaired orremoved to restore normal coronary arterial blood flow.

Referring in more detail to FIG. 1, the coronary sinus occlusioncatheter 120 can be delivered via the venous system to the coronarysinus 20 before, during, or after repairing or treating the blockage 35the coronary artery 40. In such circumstances, the portion of heartmuscle tissue 30 that is damaged due to lack of arterial blood flow (asa result of the blockage) can be treated with a supply of venous bloodwhile the normal arterial blood flow is restored (as a result ofrepairing or removing the blockage 35).

The system 100 may include a guide member 110 that is advanced throughthe venous system of the patient and into the right atrium 11. The guidemember 110 in this embodiment comprises a guide sheath having a lumenextending between a distal end 111 (FIG. 1) and a proximal end (notshown). In alternative embodiments, the guide member 110 can include aguide wire having an exterior surface extending between the distal endand the proximal end. Optionally, the guide member 110 includes asteerable mechanism to control the orientation of the distal end so asto steer the distal end 111 through the venous system and into the rightatrium 11. Also, the guide member 110 can include one or more markerbands along the distal end 111 so that the position of the distal endcan be monitored during advancement using an imaging device.

After the guide member 110 is advanced into the right atrium 11, thedistal end 111 may be temporarily positioned in the coronary sinus 20.From there, the distal tip portion 121 of the coronary sinus occlusioncatheter 120 can be slidably advanced along the guide member 110 forpositioning inside the coronary sinus 20. In the embodiments in whichthe guide member 110 comprises a guide sheath, the distal tip portion121 of the coronary sinus occlusion catheter 120 can slidably engagewith an interior surface of the lumen during advancement toward thecoronary sinus 20. In the alternative embodiments in which the guidemember 110 comprises a guide wire structure, the distal tip portion 121of the coronary sinus occlusion catheter 120 can slidably advance overthe exterior surface of the guide wire (e.g., a lumen of the catheter120 passes over the guide wire) during advancement toward the coronarysinus 20. After the coronary sinus occlusion catheter 120 reaches thecoronary sinus 20, the distal end 111 of the guide member 110 can bewithdrawn from the coronary sinus 20 and remain in the right atrium 11during use of the coronary sinus occlusion catheter 120.

Still referring to FIG. 1, the distal tip portion 121 of the coronarysinus occlusion catheter 120 that is positioned in the coronary sinus 20includes an occlusion component 122, which in this embodiment is in theform of an inflatable balloon device. The occlusion component 122 can beactivated so as to occlude the coronary sinus 20 and thereby causeredistribution of the venous blood into the heart muscle tissue 30 thatis damaged due to a lack of arterial blood flow. As described in moredetail below, the inflatable balloon device 122 can be in fluidcommunication with an internal lumen of the coronary sinus occlusioncatheter 120, which is in turn in communication with a pneumaticsubsystem of the control system 140 (FIG. 2). As such, the controlsystem 140 can be employed to expand or deflate the balloon device 122in the coronary sinus.

The distal tip portion 121 also includes a one or more distal ports 129that are positioned distally forward of the inflatable balloon device.In the depicted embodiments, the distal ports 129 face is a generallyradially outward direction and are substantially uniformly spaced apartfrom one another along the circumference of the distal tip. As describedin more detail below, the distal ports 129 may all be in fluidcommunication with a single pressure sensor lumen extending through thecoronary sinus occlusion catheter 120. Accordingly, the coronary sinuspressure can be monitored via a pressure sensor device that is in fluidcommunication with the distal ports 129.

Referring now to FIG. 2, the proximal portion 131 of the coronary sinusocclusion catheter 120 and the control system 140 are positionedexternal to the patient while the distal tip portion 121 is advancedinto the coronary sinus 20. The proximal portion 131 includes theproximal hub 132 that is coupled to the control system 140 via a set offluid or sensor lines 133, 134, and 135. As such, the control system 140can activate or deactivate the occlusion component 122 at the distal tipportion 121 of the coronary sinus occlusion catheter 120 while alsoreceiving one or more sensor signals that provide data indicative ofheart characteristics (e.g., coronary sinus pressure, electrocardiogram(ECG) information, and the like).

The proximal hub 132 of the coronary sinus occlusion catheter 120 servesto connect the plurality of fluid or sensor lines 133, 134, and 135 withthe portion of the coronary sinus occlusion catheter 120 that extendsinto the patient's venous system. For example, the first line 133extending between the control system 140 and the proximal hub 132comprises a fluid line through which pressurized fluid (e.g., helium,another gas, or a stable liquid) can be delivered to activate theocclusion component (e.g., to inflate the inflatable balloon device122). The fluid line 133 is connected to a corresponding port 143 of thecontrol system 140 (e.g., the drive lumen port in this embodiment) sothat the line 133 is in fluid communication with the control andinflation device 200 (refer to FIG. 3) at least partially housed in thecontrol system 140. The proximal hub 132 joins the first line 133 with aballoon control lumen extending through the coronary sinus occlusioncatheter 120 and to the inflatable balloon device 122.

In another example, the second line 134 extending between the controlsystem 140 and the proximal hub 132 comprises a balloon sensor line thatis in fluid communication with the interior of the inflatable balloondevice 122 so as to measure the fluid pressure within the balloon device122. The proximal hub 132 joins the second line 134 with a balloonpressure lumen extending through the coronary sinus occlusion catheter120 and to the inflatable balloon device 122. The pressure of theballoon device 122 may be monitored by a component of the control andinflation device 200 (refer to FIG. 3) at least partially housed in thecontrol system 140. The balloon sensor line 134 is connected to acorresponding port 144 of the control system 140 so that a pressuresensor arranged within the control system 140 can detect the fluidpressure in the balloon device 122. Alternatively, the pressure sensormay be arranged in the distal tip portion 121 or the in the proximal hub132 such that only a sensor wire connects to the corresponding port 144of the control system 140.

The proximal hub also connects with a third line 135 extending from thecontrol system 140. The third line 135 comprises a coronary sinuspressure line that is used to measure the fluid pressure in the coronarysinus both when the balloon device 122 is inflated and when it isdeflated. The proximal hub 132 joins the third line 135 with a coronarysinus pressure lumen extending through the coronary sinus occlusioncatheter 120 and to the distal ports 129 that are forward of the balloondevice 122. As such, the coronary sinus pressure lumen 125 and at leasta portion of the third line 135 may operate as fluid-filled path (e.g.,saline or another biocompatible liquid) that transfers the bloodpressure in the coronary sinus 20 to pressure sensor device 136 along aproximal portion of the third line 135. The pressure sensor device 136samples the pressure measurements (which are indicative of the coronarysinus pressure) and outputs an sensor signal indicative of the coronarysinus pressure to the corresponding port 145 of the control system 140for input to an internal control circuit (which may include one or moreprocessors that execute instructions stored on one or more computermemory devices housed in the control system 140). As described in moredetail below, the coronary sinus pressure data are displayed by thegraphical user interface 142 in a graph form so that a cardiologist orother user can readily monitor the trend of the coronary sinus pressurewhile the coronary sinus 20 is in an occluded condition and in annon-occluded condition. Optionally, the graphical user interface 142 ofthe control system 140 can also output a numeric pressure measurement onthe screen so that the cardiologist can readily view a maximum coronarysinus pressure, a minimum coronary sinus pressure, or both. Inalternative embodiments, the pressure sensor device 136 can beintegrated into the housing of the control system 140 so that the thirdline 135 is a fluid-filled path leading up to the corresponding port145, where the internal pressure sensor device (much like the device136) samples the pressure measurements and outputs a signal indicativeof the coronary sinus pressure.

Still referring to FIG. 2, the system 100 may include one or more ECGsensors 149 to output ECG signals to the control system 140. In thisembodiment, the system 100 includes a pair of ECG sensor pads 149 thatare adhered to the patient's skin proximate to the heart 10. The ECGsensors 149 are connected to the control system 140 via a cable thatmates with a corresponding port 149 along the housing of the controlsystem 140. As described in more detail below, the ECG data can bedisplayed by the graphical user interface 142 in a graph form so that acardiologist or other user can readily monitor the patient's heart rateand other characteristics while the coronary sinus is in an occludedcondition and in an non-occluded condition. Optionally, the graphicaluser interface 142 of the control system 140 can also output numericheart rate data (based on the ECG sensor data on the screen so that thecardiologist can readily view the heart rate (e.g., in a unit of beatsper minutes). The ECG sensor signals that are received by the controlsystem 140 are also employed by the internal control circuit so as toproperly time the start of the occlusion period (e.g., the start time atwhich the balloon device 122 is inflated) and the start of thenon-occlusion period (e.g., the start time at which the balloon device122 is deflated).

As shown in FIG. 2, the coronary sinus occlusion catheter 120 isdelivered to the heart 10 via a venous system using any one of a numberof venous access points. Such access points may be referred to as PICSOaccess points in some embodiments in which the coronary sinus occlusioncatheter 120 is controlled to perform a PICSO procedure for at least aportion of the time in which the catheter 120 is positioned in thecoronary sinus 20. For example, the guide member 110 and the distal tipportion 121 can be inserted into the venous system into an access pointat a brachial vein, an access point at a subclavian vein, or at anaccess point at a jugular vein. From any of these access points, theguide member 110 can be advanced through the superior vena cava and intothe right atrium 11. Preferably, the guide member 110 is steered into anostial portion of the coronary sinus 20, and then the distal tip portion121 of the catheter 120 is slidably advanced along the guide member 110and into the coronary sinus 20 before the guide member 110 is backed outto remain in the right atrium 11. In another example, the guide member110 and the distal tip portion 121 can be inserted into the venoussystem into an access point at a femoral vein. In this example, theguide member 110 can be advanced through the inferior vena cava and intothe right atrium 11. As previously described, the distal tip portion 121of the catheter 120 is slidably advanced along the guide member 110 andinto the coronary sinus 20 before the guide member 110 is backed out toremain in the right atrium 11.

In some embodiments, the blockage 35 in the heart may be repaired orremoved using a percutaneous coronary intervention (PCI) instrument suchas an angioplasty balloon catheter, a stent delivery instrument, or thelike. The PCI instrument may access the arterial system via any one of anumber of PCI access points, as shown in FIG. 2. In someimplementations, the PCI instrument can be inserted into the arterialsystem into an access point at a femoral artery, an access point at aradial artery, or an access point at a subclavian artery. Thus, aspreviously described, some embodiments of the system 100 may employ aPICSO access point into the venous system while a PCI access point isemployed to insert a PCI instrument into the arterial system.

Referring now to FIG. 3, some embodiments of the control system 140include the control and inflation device 200 having components toinflate and deflate the balloon device 122 of the catheter 120. Aspreviously described, the control system may further include one or moreprocessors (not shown in FIG. 3) that are configured to execute varioussoftware modules stored on at least one memory device (not shown in FIG.3). In some embodiments, a balloon inflate and deflate software modulecan be stored on the memory device to provide computer-readableinstructions that, when executed by one of the processors (such as anembedded microprocessor), causes the control and inflation device 200 toinflate or deflate the balloon device 122 at selected times. In someembodiments, the balloon inflate and deflate software module stored onthe memory device can implement a customized algorithm that calculatesand updates the time periods during which the coronary sinus is in anoccluded state and in a non-occluded state based upon the coronary sinuspressure measurements. In such circumstances, the coronary sinus 20 isnot occluded and non-occluded according to a predetermined pattern ofinflated times and deflated times that are independent of the patient,but instead the coronary sinus pressure measurements at least partiallydictate the time periods during which the coronary sinus is in anoccluded state and in a non-occluded state. In alternative modes, theballoon inflate and deflate software module stored on the memory devicemay cause the coronary sinus 20 to be occluded and non-occludedaccording to a predetermined pattern of inflated times and deflatedtimes that are independent of the patient and the coronary sinuspressure measurements. The processors of the control system 140 mayinclude, for example, microprocessors that are arranged on a motherboardso as to execute the control instructions of the control system 140. Thememory device of the control system 140 may include, for example, acomputer hard drive device having one or more discs, a RAM memorydevice, that stored the various software modules.

As shown in FIG. 3, the control and inflation device 200 can beconfigured to promptly inflate or deflate the balloon device 122. Theballoon device 122 is connected to the connection 203 of the control andinflation device via an inflation lumen 202. The pressure in theinflation lumen 202 can be measured via a schematically illustratedpressure measuring device 204. A further measurement for the balloonpressure can be obtained via a further pressure measuring device 205.The pressure measuring device 205 is connected with the balloon 122 viaa separate pressure measuring lumen 206.

The control and inflation device comprises a pressure tank 207, whichcan be connected via the control valves 208 or 224 either with theconnection 203 via line 209 or with the fluid loop via line 210.Pressure measuring devices for measuring the pressure prevailing in thepressure tank 207 are designated by reference numbers 232 and 233.Furthermore, a pump 211 is provided in parallel with a stop valve 212(and, optionally, a throttle valve). A conductive connection between thepump 211 and the vacuum tank 216 can be established via a stop valve 214and a line 215. The condensate possibly collecting in the vacuum tank216 is schematically indicated at 217 and can be pumped off via a stopvalve 218 by the aid of the condensate pump 219. Connection lines 220and 221 can be brought into a conductive connection with the vacuum tank216 via a stop valve 222. In order to determine the pressure prevailingin the vacuum tank 216 a pressure measuring device 226 is provided.

An emergency valve is denoted by 223.

The feed-in for the fluid loop takes place via line 227, to which afluid reservoir 230, e.g. a helium cylinder, may be connected via athrottle valve 228 and a stop valve 229.

In the following, the mode of functioning of the control and inflationdevice will be explained in more detail.

Set-Up Mode:

In the set-up mode, all components of the system are initially filledwith air or the like, and the valves are closed.

Evacuation:

In the evacuation mode, the whole system is evacuated. To this end, thestop valves 223 and 229 are closed, whereas all other valves are open.The air possibly present in the system is evacuated by the aid of thecondensate pump 219, the air possibly present in the system escapingalong arrow 231. The balloon 122 is also evacuated and deflated.

In the evacuated state a leak-tightness test can be conducted. Inparticular the leak-tightness of the control and inflation device, theballoon and the catheter as well as possible further volumes connectedthereto can be checked, whereby the components can be regarded as tightif the evacuated state is maintained over a predetermined period oftime.

System Filling:

The system is then filled with a fluid, e.g. helium, from the fluidreservoir 230. To this end, valves 208, 212, 214, 228 and 229 are in theopened state. All other valves are closed. As long as the stop valve 229is opened, the system is filled with helium from the reservoir 230 suchthat the pressure tank 27, the pump 211, lines 210 and 215 as well asthe vacuum tank 216 are being uniformly filled with helium.

Biasing:

After having terminated the filling procedure, stop valve 229 is closedand valve 212 is, furthermore, closed. Valve 208 remains in the stateconnecting the pressure tank 207 with line 210. In order to bias thesystem, the pump 211 is set in operation, pressing fluid from the vacuumtank 216 into the pressure tank 207. The process is carried out until areleased fluid amount has reached the pressure tank 207 and apredetermined pressure difference has adjusted between the vacuum tank216 and the pressure tank 207 or a predetermined pressure has beenreached in the pressure tank 207, respectively. It may, for instance, beproceeded in a manner that a pressure of 3 bar is reached in thepressure tank 207, while the pressure in the vacuum tank 216 is reducedto 0.6 bar. After having completed the biasing of the system, all valvesare closed.

Balloon Inflation:

To inflate the balloon 122, valve 224 is opened so that the pressuretank 207 is connected with the connection 203, and hence with theballoon 122, via line 209. Pressure equalization consequently occursbetween the pressure tank 207 and the balloon 122, with valve 224 beingmaintained in the opened position until full pressure equalizationbetween the pressure tank 207 and the balloon 122 has occurred. Afterfull pressure equalization has been achieved, the balloon 122 and thepressure tank 207 are under the same pressure, for instance under apressure of 1.2 bar.

Balloon Evacuation:

To evacuate the balloon, valve 222 is opened and valve 224 is closed,thereby disconnecting the pressure tank 207 from the connection 203. Theballoon 122 is then directly connected with the vacuum tank 216 suchthat the evacuation of the balloon 122 is caused by pressureequalization between the balloon 122 and the vacuum tank 216. After fullpressure equalization has been achieved, the balloon 122 and the vacuumtank 216 are under the same pressure, the pressure level being, forinstance, 0.8 bar, yet in any case less than 1 bar.

The cycle of inflating and evacuating the balloon 122 can be repeatedany number of times. For a renewed inflation of the balloon 122, thesystem may again be biased, to which end valve 222 is closed and valve14 is opened. As before, valve 208 is in an open state in which thepressure tank 207 is connected with line 210 and valve 224 is closed.When the pump 211 is set in operation, fluid is sucked from the vacuumtank 216 and pressed into the pressure tank 207. To fill the balloon122, valve 214 is again closed and valves 208 and 224 are switched suchthat the pressure tank 207 is connected with the connection 203, andhence with the balloon 122. After a pressure equalization of thepressure tank 207 and the balloon 122, the balloon is again filled. Theevacuation of the balloon is again effected by switching valves 208 and224 and opening valve 222 so as to connect the balloon 122 with thevacuum tank 216, thus causing fluid to flow from the balloon 122 intothe vacuum tank 216 until pressure equalization between the balloon 122and the vacuum tank 216 has occurred.

It should be apparent from the description herein that both the fillingof the balloon 122 and the evacuation of the balloon 122 are simplyeffected due to a full pressure equalization with the pressure tank 207,on the one hand, and with the vacuum tank 216, on the other hand. Thefluid is simply recirculated so as to enable a particularly economicalmode of operation and a reduction of the energy consumption.

As a security measure valves 208 and 224 are blocked to each other in ahardware manner such that they cannot both be opened or both be closedat the same time.

As a further security measure the emergency valve 223 is opened if apressure overload is detected based on the measurements of the pressuremeasurement devices 204, 205, 213, 225, 232, 233 and 234.

System Cleaning:

For cleaning purposes, valve 222 is opened and valve 208 is placed intoa position in which the pressure tank 207 is connected with line 210.All other valves are closed. Condensate possibly collecting in thevacuum tank 216 can subsequently be pumped off by the vacuum-condensatepump 219.

The method of cyclically filling the balloon 122 can be realized in theform of a control algorithm which can be realized as a hardware circuit(electronic wiring with relays and flipflops) or software in amicrocontroller. Typically, the realization is a software typerealization, such as the software module as previously described.

The control algorithm can function as follows (when the computersoftware instructions are executed by the processor) to perform thefollowing operations:

-   -   Determining the volume of the catheter with the balloon being in        a deflated state based on at least two subsequent pressure        measurements with two different pressures in the pressure tank        207. Thereby at least four measurement values (pressures at 204        and 205) are measured.    -   Measuring the pressures at 204 for a predetermined pressure at        232.    -   Stepwise raising the pressure in the pressure tank 207 until a        predetermined or selected target value for the pressure at 204        is attained.

This is performed in the form of a control algorithm that is implementedas software instructions stored on a computer-readable memory device inthe control system 140. In some embodiments, the control and inflationdevice 200 advantageously comprises a multi processor system, apneumatic fluid circuit and an embedded PC for controlling an MMI forthe application specific representation and evaluation of applicationand measurement data during one treatment. The multi processor systemcomprises at least two independent electronic circuits which monitor thesecurity relevant function in a fail-safe manner.

According to some embodiments described herein, a method for determininga patient- and/or catheter-specifically optimized fluid amount forfilling a balloon of a balloon catheter arranged in a body vessel toinflate the former is provided. The method may include the followingsteps:

a) evacuating the balloon,

b) providing a defined starting amount of fluid and using this startingamount for filling the balloon as well as measuring the balloon startingpressure,

c) providing a fluid amount increased relative to the preceding amountand using the increased amount for filling the balloon as well asmeasuring the balloon pressure, resulting from the filling or measuringvariations thereof,

d) comparing the measured balloon pressure or the variations thereofwith a predetermined target value and repeating step c) until theballoon pressure or the variations thereof has reached said targetvalue,

e) storing the last-provided fluid amount as a reference value forinflating the balloon.

The aforementioned method can be used to determine a patient- and/orcatheter-specifically optimized fluid amount for filling the balloonduring the preparation of the occlusion procedure. Thus, prior toperforming the patient's treatment, the optimum fluid amount for fillingthe balloon can be determined by the aforementioned method, with theoptimum fluid amount determined being used as a reference value for thesubsequent treatment of the patient, and the control and inflationdevice 200 for the balloon catheter 122 being adjusted to the patient-or catheter-specific value in this manner. During the subsequentocclusion cycles, the value determined using the aforementioned methodis maintained or adjusted in order to take into account changes of thecircumstances occurring during treatment. Adjusting the patient- and/orcatheter-specifically determined value will be appropriate if, forexample, the pressure conditions in the occluded vessel have changed, ifthe visco-elasticity of the vessel has changed, or if the treatment isshifted to another vessel site.

At the beginning of the method, the balloon 122 may be evacuated inorder to bring the balloon 122 to a defined pressure level which servesas the starting point for the subsequent method steps. According to stepb), a defined starting amount of fluid is provided and the startingamount is used for filling the balloon, whereupon the balloon pressureresulting from said starting amount is measured. According to step c),the preceding fluid amount can be increased and the balloon pressureresulting from the increased fluid amount is measured. The determinedballoon pressure is compared with a predetermined target value, and thefluid amount used for filling the balloon may be gradually increaseduntil the balloon pressure has reached the predetermined target value. Atarget value may, for instance, be an absolute value of at least 70 mmHg, in particular approx. 80 mm Hg, independent of the patientconcerned. The target value may, however, also be chosen as a functionof the patient and, for instance, lie 10% above the maximum pressureresulting in the respective patient during the occlusion in the occludedvessel.

In order to achieve the predetermined target value, a differently stronginflation of the balloon (e.g., a differently large amount of introducedfluid) may be employed as a function of the visco-elasticity of thevessel, other patient-dependent factors and the catheter type. Thegradual approach during the introduction of the fluid into the balloon122 as in correspondence with the invention prevents the pressure in theballoon to exceed a predetermined target value. By defining as areference value the fluid amount introduced into the balloon andcorresponding to the target value, a pressure measurement in the balloonmay (in some circumstances) be obviated during the subsequent inflationprocedure, and the inflation procedure may be exclusively controlled onaccount of the introduced fluid amount. By limiting the introduced fluidamount, simple control of the inflation procedure is feasible whilesafeguarding against inadmissible operating states such as, inparticular, inadmissible pressure states. If the reference value is beadjusted during subsequent inflating procedures, the balloon pressuremay be continuously determined so that deviations of the balloonpressure from the target value can be detected, whereby the referencevalue is adjusted, if the detected deviation exceeds a predeterminedlimit of tolerance.

In some embodiments, a continuous pressure measurement is also useful,if the balloon pressure shall be monitored not only with regard to theholding of the target value but also with regard to exceeding a securityrelevant upper limit. Such an upper limit orients itself at values whichare deemed as being permissive with regard to the operating security ofthe catheter, e.g. with respect to the bursting of the balloon or thecoronary sinus vessel, and can have values of e.g. between 90 and 120 mmHg. If the upper limit value is exceeded, the system can be stoppedimmediately.

According to an alternative embodiment, variations of the balloonpressure may be determined and analyzed instead of the absolute pressureprevailing in the balloon. Pressure variations can occur, if the balloonis inflated to an extent that the balloon touches the vessel wall,whereby the blood flow in the small gap between the balloon approachingthe vessel wall and the vessel wall cause characteristic flow conditionsthat result in pressure variations in the balloon. Such pressurevariations indicate that the balloon reaches the vessel wall.

According to some embodiments, the aforementioned steps b) to d) maycomprise establishing a pressure-volume curve from the balloon startingvolume resulting from using the starting amount and from the balloonstarting pressure as well as the balloon volumes respectively resultingfrom using the gradually increased fluid amounts and from the respectiveballoon pressures. By way of the pressure-volume curve, it is feasiblein a simple manner to observe and track the gradual approach to theoptimum balloon filling, the course of the pressure-volume curve as arule being such that in a first region, in which the balloon does notyet touch the vessel wall, the introduced fluid volume rises at a nearlyconstant or slightly increasing pressure and in a second region, inwhich the balloon abuts on the vessel wall, the internal pressure of theballoon significantly rises at every increase of the introduced fluidvolume.

According to some embodiments, the balloon 122 may be evacuated prior toevery performance or repetition of the aforementioned step c). Such anoperation may ensure that a defined starting state is provided for eachof the gradual increases in the fluid amount introduced into the balloon122 in the course of the gradual approach to the target value of theballoon pressure, the balloon 122 after every evacuation being filledwith a fluid amount increased relative to the preceding amount. In orderto achieve the same evacuation state at every evacuation procedure, theballoon pressure may be measured during the evacuation of the balloonand said evacuation is effected until a predetermined negative pressureis reached. The predetermined negative pressure may be chosen to be thesame at each evacuation. During the evacuation of the balloon 122, thepressure can additionally also be measured in the negative pressuresource being responsible of the evacuation of the balloon.Advantageously, the pressure in the vacuum tank 216 can be measured inorder to monitor if a predetermined negative pressure is attained.

The evacuation of the balloon 122 prior to each increase of the fluidamount introduced into the balloon 122 may also result in the balloon122 being regularly deflated in the course of the method according tothe invention, thus preventing too long an impairment or interruption ofthe flow in the concerned body vessel (e.g., the coronary sinus in someembodiments).

According to particular embodiments, it is provided that the increase inthe fluid amount may be gradually effected by a value which ispreferably the same at every increase.

According to some embodiments, the inflation of the balloon 122 iseffected in that the starting amount of fluid and the respectivelyincreased fluid amount are dosed into the pressure tank 207 and theballoon 122 is filled exclusively due to full pressure equalizationbetween the pressure tank 207 and the balloon 122. The fluid is thus notdirectly filled into the balloon, since this would entail the risk of anuncontrolled amount of fluid entering the balloon in the event of amalfunction. If, as is preferably provided, the fluid is at first dosedinto the pressure tank 207, the fluid amount can be precisely controlledand a malfunction would only result in the pressure tank 207 beingfilled with an excessive amount, which would, however, be detected orchecked prior to the inflation of the balloon 122. With the respectivelyprovided amount of fluid dosed into the pressure tank 207, filling ofthe balloon 122 is simply effected by opening the connection between thepressure tank 207 and the balloon 122, thus causing the balloon 122 tofill exclusively due to a full pressure equalization between thepressure tank 207 and the balloon 122.

According to an exemplary mode of operation, the pressure measured inthe pressure tank 207 can be used for controlling the dosing of thedesired amount of fluid into the pressure tank 207. With regard to theamount of fluid stored as a reference value, this means that thepressure that prevails due to the filling of the pressure tank 207 withthe reference amount of fluid is stored as the reference pressure andthe filling is carried out until the reference pressure is reached sothat the control of the filling procedure of the pressure tank 207 issimplified.

According to a further mode of operation, it is provided that theballoon pressure is measured via a catheter lumen 206 separate from thecatheter lumen 202 provided for filling. This will lead to an enhancedsafety, in particular, if the balloon pressure is also measured in thecatheter lumen provided for filling. In this manner, two independentpressure measurements are available, and possible malfunctions can beconcluded from a comparison of these pressure values.

According to particular embodiments described herein, a method forinflating and evacuating the balloon 122 of the balloon catheter 120 isprovided, in which the balloon 122 is connected with a positive pressuresource for inflation and with a negative pressure source for evacuationand which is characterized in that the pressure tank 207 which is filledwith fluid under positive pressure is provided as said positive pressuresource, and that the inflation of the balloon 122 is effectedexclusively due to a full pressure equalization between the pressuretank 207 and the balloon 122. By the inflation of the balloon 122 beingeffected exclusively due to a full pressure equalization between thepressure tank 207 and the balloon 122, malfunctions such as overfillingof the balloon 122 beyond the maximum pressure may be effectivelyavoided. The pressure tank 207 is initially filled with a predeterminedfluid amount, said fluid amount being measured such that a predeterminedfilling state and pressure state will result in the balloon 122. Whenthe connection between the prefilled pressure tank 207 and the balloon122 is opened, a predetermined filling state of the balloon 122 willadjust due to the full pressure equalization between the pressure tank207 and the balloon 122, thus causing the body vessel (e.g., thecoronary sinus) to be occluded. By the filling of the balloon 122 beingexclusively effected due to a full pressure equalization between thepressure tank 207 and the balloon 122, separate regulation and controlmeasures can be obviated during filling, and an inadmissible fillingstate of the balloon may be prevented in that only the fluid amountinitially dosed into the pressure tank 207 will reach the connectionline and the balloon 122 because of the subsequent pressureequalization.

An additional control can be advantageously performed, if the inflationtime is monitored. In case the inflation time lies below a lower limitvalue such as, e.g., 0.2 sec, an error message will be generated or thesystem shuts down. A too fast inflation might result in damage of thevessel. In case the inflation time lies above a predetermined upperlimit value such as, e.g., 0.50 sec, an error message is also generatedor the system shuts down. An inflation that lasts too long may result inthat the blood flow in the respective vessel is impeded for a too longtime.

A further control can advantageously be carried out when the deflationtime is monitored. If the deflation time lies below a predeterminedlower limit value such as, e.g., 0.5 sec, an error message is generatedor the system shuts down. If the balloon collapses too fast, this mightpossibly lead to damage of the vessel.

In some embodiments, a cycle comprising the evacuation and inflation ofthe balloon may be advantageously performed by a sequence of thefollowing steps:

a) connecting the balloon with a negative pressure source to evacuatethe balloon, in particular to a predetermined negative pressure,

b) interrupting the connection between the balloon and the negativepressure source,

c) dosing a predetermined fluid amount into the pressure tank, thusfilling the latter with fluid under positive pressure,

d) opening the connection between the pressure tank and the balloon,whereby the inflation of the balloon is exclusively effected due to afull pressure equalization between the pressure tank and the balloon,

e) closing the connection between the pressure tank and the balloonafter full pressure equalization has occurred.

In an example mode of operation of this method, the vacuum tank 216 maybe employed as said negative pressure source, the fluid preferably beingrecirculated between the vacuum tank 216, the pressure tank 207 and theballoon 122, thus offering the advantage that no new fluid need be fedinto the loop even with a plurality of inflation and evacuation cycles.An advantageous mode of operation in this respect provides that thefilling of the pressure tank 207 comprises the suction of fluid from thevacuum tank 216 forming the negative pressure source.

In some circumstances, it is further provided that the filling of thepressure tank 207 is effected by the aid of the pump 211 arrangedbetween the pressure tank 207 and the vacuum tank 216.

The method can be advantageously carried out in that the fluid systemcomprising the pressure tank 207, the pump 211, the vacuum tank 216 andthe balloon 122 as well as the connection lines is filled with such anamount of fluid that the pressure within the system is smaller than 2bar at a full pressure equalization of all components. This will lead toa substantial enhancement of the operating safety, since it is ensuredthat an uncontrolled fluid amount will not enter the balloon 122 even ifall of the safety valves or other safety devices have failed. In themost extreme case, pressure equalization would take place within thewhole system at a valve failure, which, due to the overall quantity ofthe fluid present within the system, would result in a pressure of <2bar so that an accordingly deflated state of the balloon 122 would beobtained.

According to a further aspect, the control and inflation device 200 ofthe control system 140 may comprise a connection for the inflation lumen202 (refer also to the drive lumen 133 in FIG. 2) of the ballooncatheter 120, wherein switching valves are arranged in a manner that theconnection for the inflation lumen 202 is alternately connectable withthe vacuum tank 216 and with the pressure tank 207. In a preferredmanner, it is provided the pressure tank 207 is alternately connectablewith the connection for the inflation lumen 202 and, via the pump 211,with the vacuum tank 216.

In some embodiments, the connection for a catheter lumen separate fromthe inflation lumen is provided, which is connected with a pressuremeasuring device.

In some embodiments, the pressure tank 207, the pump 211 and the vacuumtank 216 preferably form a closed fluid loop together with the inflationlumen 202 of the catheter. The closed loop preferably comprises aconnection for filling the loop with fluid.

According to some embodiments, a control inflation apparatus for theballoon catheter 120 is provided comprising the pressure tank 207 forfluid, a dosing unit (e.g., the pump 211) for dosing fluid into thepressure tank 207, the connection 202 for a filling lumen of the ballooncatheter 120, which connection can be connected to the pressure tank 207via a switchable valve 24, at least one pressure measuring device formeasuring the fluid pressure prevailing in the balloon 122 of theballoon catheter 120, and a control circuit to which the measuringvalues of the pressure measuring device are fed and which cooperateswith the dosing unit for dosing a defined fluid amount into the pressuretank as a function of the pressure measurement values.

In one aspect, the control circuit cooperates with the switchable valvesuch that the switchable valve is closed if the dosing unit doses fluidinto the pressure tank. The dosing unit can be comprised of a pump forexample.

According to a further aspect, a pressure measuring device measuring thefluid pressure prevailing in the pressure tank can be provided, themeasuring values of which are fed to the control circuit whereby astorage is provided for an upper pressure target value and the controlcircuit cooperates with the dosing unit such that dosing of fluid intothe pressure tank is terminated if the pressure measured in the pressuretank reaches the pressure target value.

A number of embodiments of the invention have been described.Nevertheless, it will be understood that various modifications may bemade without departing from the scope of the invention. Accordingly,other embodiments are within the scope of the following claims.

What is claimed is:
 1. A control and inflation device for a ballooncatheter, comprising a pressure tank for fluid, a dosing unit for dosingof fluid into the pressure tank, a connection for an inflation lumen ofthe balloon catheter which can be connected with the pressure tank via acontrol valve, a first pressure measuring device for measuring the fluidpressure prevailing in a balloon of the balloon catheter and a controlcircuit to which balloon pressure values detected by the pressuremeasuring device are fed and which cooperates with the dosing unit fordosing a defined amount of fluid into the pressure tank as a function ofthe balloon pressure values.
 2. The control and inflation device ofclaim 1, wherein the control circuit cooperates with the control valvesuch that the control valve is closed if the dosing unit doses fluidinto the pressure tank.
 3. The control and inflation device of claim 1,wherein the dosing unit comprises a pump.
 4. The control and inflationdevice of claim 1, further comprising a second pressure measuring devicefor measuring the fluid pressure prevailing in the pressure tank,wherein pressure tank values detected by the second pressure measuringdevice are fed to the control circuit for comparison to a predeterminedtarget value, wherein the control circuit cooperates with the dosingunit such that dosing of fluid into the pressure tank is terminated ifthe fluid pressure prevailing in the pressure tank reaches thepredetermined target value.
 5. The control and inflation device of claim1, wherein the balloon catheter comprises a coronary sinus occlusioncatheter having an inflatable balloon along a distal end portion that issized to intermittent occlude a coronary sinus of a heart.
 6. Thecontrol and inflation device of claim 1, further comprising a secondpressure measuring device and a connection to provide in fluidcommunication between the second pressure measuring device and a centralcatheter lumen of the balloon catheter that is separate from theinflation lumen of the balloon catheter.
 7. The control and inflationdevice of claim 1, wherein the balloon of the balloon catheter is filledexclusively due to full pressure equalization between the pressure tankand the balloon when the control is arranged in a manner that connectsthe connection for the inflation lumen with the pressure tank.
 8. Thecontrol and inflation device of claim 1, further comprising a vacuumtank, wherein the control valve and a second valve are arranged in amanner that the connection for the inflation lumen is alternatelyconnectable with the vacuum tank and with the pressure tank.
 9. Thecontrol and inflation device of claim 8, wherein the pressure tank isalternately connectable with the connection for the inflation lumen and,via the dosing unit, with the vacuum tank.
 10. The control and inflationdevice of claim 8, wherein the pressure tank, the dosing unit and thevacuum tank form a closed fluid loop together with the inflation lumenof the catheter.
 11. The control and inflation device of claim 10,wherein the closed loop comprises a connection for filling the loop withhelium.
 12. The control and inflation device of claim 8, furthercomprising a condensate pump connected to the vacuum tank.
 13. Thecontrol and inflation device of claim 8, wherein the control valve andthe second valve are configured to switch the inflation lumen to aconnection with the vacuum tank immediately in response to the firstpressure measuring device detecting a pressure prevailing in the balloonreaching a value greater than an upper limit selected between 90 and 120mm Hg.
 14. The control and inflation device of claim 8, wherein theballoon of the balloon catheter is filled exclusively due to fullpressure equalization between the pressure tank and the balloon when thecontrol valve and the second valve are arranged in a manner thatconnects the connection for the inflation lumen with the pressure tank.15. The control and inflation device of claim 14, wherein the balloon ofthe balloon catheter is evacuated exclusively due to full pressureequalization between the vacuum tank and the balloon when the controlvalve and the second valve are arranged in a manner that connects theconnection for the inflation lumen with the vacuum tank.
 16. The controland inflation device of claim 14, wherein an inflation time for fillingthe balloon is monitored to detect a time required to provide fullpressure equalization between the pressure tank and the balloon, andwherein the control circuit generates an error message in response tothe inflation time being detected below a lower limit value of 0.2 sec.17. The control and inflation device of claim 14, wherein an inflationtime for filling the balloon is monitored to detect a time required toprovide full pressure equalization between the pressure tank and theballoon, and wherein the control circuit generates an error message inresponse to the inflation time being detected above an upper limit valueof 0.50 sec.
 18. The control and inflation device of claim 15, wherein adeflation time for evacuating the balloon is monitored to detect a timerequired to provide full pressure equalization between the vacuum tankand the balloon, and wherein the control circuit generates an errormessage in response to the deflation time being detected below a lowerlimit value of 0.5 sec.